Field of the Invention
The present invention relates to an ink, an ink cartridge, and an ink jet recording method.
Description of the Related Art
The recording speed of ink jet recording apparatuses has been dramatically improved as a result of the technical advance. Such ink jet recording apparatuses have been gradually introduced into the field of business document printing in place of laser recording apparatuses. Ink jet recording apparatuses typically use, as inks for texts to be used for recording images on recording media such as plain paper, aqueous inks containing self-dispersible pigments as a coloring material in consideration of high optical density.
A recording head employing the system of ejecting an ink by the action of thermal energy has a large number of ejection orifices and thus is useful in terms of recording speed and the like. In the field of business document printing, the recording frequency and the recording amount are large, and thus the occurrence of kogation is required to be reduced at a higher level than ever before in the ejection system using thermal energy. For more stable ejection by the ink jet method, an ink containing a vinyl dispersion resin having a phenylsulfonylphenyl structure has been disclosed, for example (Japanese Patent Application Laid-Open No. 2008-144033).
However, the results of studies by the inventors of the present invention have shown that various additives that have been thought to be effective are not always effective for the aqueous ink containing a self-dispersible pigment as a coloring material when the ink is applied to the system of ejecting an ink by the action of thermal energy.
An object of the present invention is thus to provide an aqueous ink that contains a self-dispersible pigment as a coloring material but reduces the occurrence of kogation and enables the recording of high quality images when the ink is used in the ink jet recording method using a recording head that ejects an ink by the action of thermal energy. The present invention is also directed to provide an ink cartridge including the aqueous ink and an ink jet recording method using the aqueous ink.